Simsima eSIM Data Plans for Japan

Simsima does not provide a truly unlimited data eSIM for Japan. All plans that carry the name “Unlimited –” offer a 3GB/day cap, after which the speed is throttled to a reduced 1000kbps and the plan is not unlimited in the sense of providing high‑speed data without limits.

Travelers who need more data can choose fixed‑data plans, such as the 100GB plan valid for 180 days or the 50GB plan valid for 30 days (IIJ), both of which provide 5G connectivity in Japan and offer a more cost‑effective option for relatively heavy data users.

Simsima does not provide a phone number or SMS capability on its Japan eSIM plans; only data‑only plans are available. Travelers can still use VoIP applications such as WhatsApp, Telegram, and iMessage over the data connection for calls and messaging, but they should check that these services are accessible in Japan before purchasing.

Simsima provides 11 single‑country data plans that cover Japan and 19 multi‑country plans that include Japan as part of a broader package. The available plans range in price from approximately $0.40 to $84.53 and in data allowance from 100 MB up to 100 GB per validity period, which can last between 5 and 180 days. For Japan‑specific offers, customers can choose between plans that have a fixed data cap—such as 1 GB, 3 GB, 5 GB, 10 GB and 20 GB—or plans that apply a daily data cap, for example 200 MB per day or 1 GB per day, allowing more flexible usage over the plan’s duration. The mix of fixed and daily cap options offers users the ability to select a plan that best matches their travel data needs.